Seamless diaphragm



Sept. 10, 1935. sc A E 2,013,792

S EAMLE S S DIAPHRAGM Filed Jan. 9, 1934 IN VENT OR Efi/CH SCH/15 65 ATTORNEY byfibrousmaterlal.

Patented Sept. 10, 1935 UNITED STATES PATENT OFFICE SEAHLESS DIAPHRAGMErich Schlfer, Berlin, Germany, aaaignor to Telefunken Gesellaehaft furDrahtloae Telegraphic, Berlin. Germany, a corporation of GermanyApplication January 9, 1934, Serial No. 705,838 In Germany February 8,1983 3 Claims. (Cl. 181-82) This invention relates to diaphragms foracoustic apparatus and the like. The object of the invention is toprovide a seamless diaphragm made, from fibrous material, preferablycast 5 carton-for acoustic WW.

Diaphragms of fibrous material are fund mentally known in the prior art.However, while these diaphragms are quite serviceable in practice, theynevertheless suffer from the drawback 10 that they lack sumcientrigidity for high or heavyduty requirements in acoustical work.According to the invention thesedrawbacks are obviated by placingreinforcement ribs or fins or stiffening skeletons of refined andalloyed light metal (alu- 15 minum or beryllium alloys) or other hardand light substances in the mold during the process here disclosed beingapplied to a cone diaphragm. The fins or ribs or reinforcement membersbeing of plain or profiled form, are made of alloyed light metal and areindicated at I. They are embedded into the diaphragm consisting of 5fibrous material 2.

What I claim is: i. The method of manufacturing a diaphragm Y whichconsists in molding a diaphragm of fibrous material around areinforcingframe of rigid 6 material.

2. A diaphragm comprising a rigid reinforcing frame and a fibrous massmolded around said frame and formed into the desired diaphragm m 3.seamless diaphragm comprising a reinforcing skeleton of a light metalalloy and a molded fibrous material surrounding said'skeletonsothatsaidskeletonisimbeddedinsaidfibrousmaterial, aaid fibrous materialbeing formed into so

